How to Configuring Catalyst Switch for 3 Vlans with one DHCP Server?

[reagentom]

> Dear Sir’s

I’m new System Engineer in a College, I have Cisco Catalyst Switch 4006 with Supervisor II OS witch configured for 3 Vlans, I have DHCP Server witch is connected to Vlan 1 but it’s working as DHCP server for all computers connected to Vlan 2 and 3 each Vlan has a different IP scope (VLAN2 -172.16.20/24 and VLAN3 – 172.16.3.0/24) ..

Now I want to create new Vlan (Vlan 4) and make it obtain the IP from same DHCP server with scope (172.16.4.0/24) but the problem I don’t know how the current situation is going on and witch technology is applied for make the DHCP server serve 3 Vlans and also I don’t know how I can check if there is DHCP BOOTP Relay agent configured or not..

The attached file is a copy of show config all command.

Please Help ASAP

Best Regards

[reagentom]

it's not possible to give VLAN4 gatway 172.16.4.1 because gatway should be ip address of ISA server so can provide internet connection with our policy and filtering..

is it possible to make ip route from 4.0 network to 2.0 ?? this is the best solution for this case but sure without communicate with v3

[reagentom]

Dear ankur

Unfortunately I have tried to make the default gateway for vlan 4 as the ISA server (172.16.2.10) but the same problem still there and vlan4 pcs can communicate with both other vlans

Please Advise ASAP

[ankurbhasin]

Hi,

I am sorry i was not in office after my last reply!!

As what I understand with your network scenario is your gateway for vlan 2 AND vlan 3 are your ISA server and also your vlan 3 and 2 are not talking to each other so must be some policy defined on your ISA server.

Do the same for vlan 4. By whcih I mean do not assign it a gateway for vlan 2 network but assign the same subnet gateway for vlan 4 something like 172.16.4.x which muct be there on your ISA server so that you can go to internet from vlan 4.

Now you can have a route for vlan 4 to vlan 2 on your ISA server not sure how can we enable route on ISA server but I am sure you can have it done.

HTH

Ankur

[reagentom]

Hi Ankur,

thanks for reply, I will try to do that next satarday cuz I'm in week end for today and tomorrow I hope it's working fine by that so I will use 2 NIC card in the student server to make it available for both vlans 2, 4 without doing any routing on router it self..

Thanks

[reagentom]

Dear Ankur;

I had tried today to do what you have suggest but unfortunately without any changing and vlan 4 is able to ping both vlans 2,3.. also I removed the default gateway from DHCP configuration and make computers in vlan 4 without gateway but also without any luck.

I want to tell you something may be it’s useful to understand the problem..

When I create VLAN 4 by command “Set vlan 4 3/25” and “set vlan 4 3/26” I got this massage as a result

“Vlan 4 has been modified successfully”

“Vlan 1 has been modified successfully”

But I didn’t do any changing in Vlan 1 .. and when I had run “show vlan command” I find port 2/1 is coming as member of all vlans … but this is for first time only I mean after closing consol and relogin to the router and run the same command this port is not shown as a member of any Vlans !!!

And in show run I find this port (2/1) has some configuration as a trunk

#module 2 : 34-port Router Switch Card

set vlan 2 2/9,2/12-13,2/17-18,2/29,2/33

set vlan 3 2/6,2/8,2/11,2/20,2/23,2/25-26,2/31

set vlan 106 2/4

clear trunk 2/1 106

set trunk 2/1 on dot1q 1-105,107-1005

is it important information ??

[ankurbhasin · Accepted solution]

Hi,

Sorry for my late reply as I was busy with some work.

Yes if you configure any vlan in your switch all the trunks by default will become the member of that vlan. As port 2/1 is been configured for trunk port and you are creating a new vlan same time that port 2/1 will also become a member of that vlan.

What I will say again is configure your ISA server with one more subnet of vlan 4 network and then assign that ip as your gateway on vlan 4 machines and that will be a straight and simplest way to achive what you want.

HTH

Ankur

[reagentom]

hi ankur,

for the isa as I toled you before there is no problem I can asign one more server for vlan 4 only if I want to connect this vlan for internet but right now I don't want to connect it so I tried to keep gateway as a blank and also I tried to give it gateway in the same vlan but it's still communicated with others vlans..

I think there is some missing configuration need to be done in the switch or router to fix this problem

[reagentom]

anyone can help for this conversation please participate..

Thanks

[reagentom]

Dear Ankur;

I would like to thank you very much for your help.. the problem have been fixed after creating static route on pix from 172.16.4.0 to 172.16.1.1 like vlan2 and vlan 3 witch configured before..

Best regards

[ankurbhasin]

Hi,

Thanks a lot for your valuable vote and happy to know your scenario is working now.

So finally which is your gateway for vlan 4 PIX,ISA server or routeing blade.

I will really like to know your name if you don't mind as we really had a long conversation which I really enjoyed and finally you got things done.

Regards,

Ankur

[reagentom]

Dear Ankur,

Thanks alot for your comment, I'm ahmed said I'm egyptian working in Sultante of Oman. :)

I was very happy to solve my problem only till a few minutes back :( because I had discovered that the pc's connected to VLAN4 if it's taked gateway as roting blade or ISA server or PIX it can communicate with all server I have !!!

student server 172.16.2.9

staff server 172.16.3.6

both ISA servers (172.16.2.10, 3.8)

That's why I'm thinking there is missing configuration in my switch and I would like to access it by http to be able to manage it easyer

but after enabling the http server I can login after entering my user name and password but I got one page with the following lines only..

Accessing Cisco Catalyst Switch

--------------------------------------------------------------------------------

Help resources

CCO at www.cisco.com - Cisco Connection Online, including the Technical Assistance Center (TAC).

tac@cisco.com - e-mail the TAC.

1-800-553-2447 or 408-526-7209 - phone the TAC.

cs-html@cisco.com - e-mail the HTML interface development group.

I don't know what is this and how I can solve it..